Electrical connector for well tools



Patented Dec. 2, 1952 ELECTRICAL CONNECTOR FOR WELL TOOLS George F. Turechek, Los Angeles, and Robert A. Phillips, La Habra Heights, Calif., assignors to Lane-Wells Company, Los Angeles, Calif., a

corporation of Delaware Application December 21, 1948, Serial No. 66,442

8 Claims.

This invention relates, in general, to submergible electric connectors and more particularly to coupling devices for making electrical connections with electrically actuated or operated devices or tools submerged in conductive fluid within well boreholes.

The apparatus of this invention finds its principal utility in connection with the so-called godevil types of electrical connectors adapted to be lowered or dropped down a well borehole through tubing, drill-pipe, casing or the like into connection, at the lower end thereof, with a well tool' to be operated electrically, such as for example, an electrically fired, casing perforating gun. When the so-called go-devil is dropped or is lowered on an ordinary wire line the go-devil device may carry its own supply of electric current in the form of a battery of dry cells, storage batteries or the like, or the go-devil may be lowered on a conductor cable, in which case the current source may be located at the ground surface at the top of the well borehole and the current conducted through the conductor in the cable to the lowered go-devil and to the contactor mechanism associated therewith. In either case, suitable remotely operable means is required for making an eicient electrical coupling between the gol-devil and the electrically actuated device deep within the well borehole and while submerged in the well fluid. In either case,

but particularly where a go-devil connector device is employed which contains its own current source of supply, it is important to eliminate or at least minimize the occurrence of short circuiting current which may flow between the several connector elements thereof through the iiuid within the well through which the device is lowered. Usually the well iiuid through which such a device is lowered and in which it must operate is in the form of drilling mud which contains sufficient electrolytic materials to render it highly conductive.

In the Zschokke Patent No. 2,427,377 a connector device is disclosed which provides for maintaining the contact elements of the go-devil portion of the apparatus completely insulated from surrounding iiuids until contact is established with the terminal elements of the well tool, so that no loss of current will occur by reason of short-circuiting through the surrounding conductve fluid between the contact elements during descent. The present invention is an improvement over that of the beiorementioned Zschokke patent in that it not only maintains the godevil contacting element or elements insulated from the well uid during its descent in the well but it also maintains the well tool terminal elements with which it is to be coupled, insulated from the well fluid prior to lthe establishment of the connection, and furthermore maintains both the go-devil contacter elements and the Well tool terminal elements insulated from the well fluid during the time the electrical connection coupling is maintained between the go-devil and the well tool.

The improvements of the present invention also include a coupling arrangement between go-devil contact elements and well tool terminal elements whereby any one of two or more electrical circuits within the well tool can be selectively and separately energized by manipulation of the go-devil from the top of the well.

It is accordingly an object of this invention to furnish an improved submergible electrical coupling.

It is another object to provide a submergible electrical connector coupling which maintains all of the interconnecting contacter and terminal elements thereof insulated from surrounding conductive iiuid prior to establishment and during maintenance of the coupling connection.

It is still another object of this invention to provide a multiple element coupling device by means of which an electrical current source or supply may be coupled to any one or more of a number of separate electrical circuits within a well tool or device located at a remote position within a well borehole.

These and other objects, advantages and features of novelty will be evident hereinafter.

In the drawings, which illustrate a preferred embodiment and mode of operation of the invention and in which like characters designate the same or similar parts throughout the several views:

Figure 1 is a longitudinal sectional view of the general assembly of the apparatus of the invention as it would appear when suspended in a we borehole in readiness for operation. I

Figure 2 is an enlarged longitudinal sectional view of a portion of the apparatus of Figure l.

Figure 3 is an enlarged longitudinal sectional, detailed view of a fragmentary portion of the apparatus of Figure 2 illustrating its appearance at the completion of an initial stage of the operation of the invention.

Figure 4 is an enlarged longitudinal sectional, detailed view of a fragmentary portion of the apparatus corresponding to that of Figure 3, illustrating its arrangement and appearance at another stage in the operation of the invention.

The apparatus is as follows;

Referring i-lrst primarily to the several longitudinally interconnected housing components of the general assembly as best shown in Figure l, I is the lower end of a string of drill pipe or tubing upon which the apparatus may be lowered and suspended in a `well borehole and through which fluid produced from the well may be caused to flow under production as hereinafter more fully described. The lower threaded end of the tubing or drill pipe I0 makes threaded connection at H with the upper end of a cylindrical bumper guide housing I2 which in turn makes threaded connection at I3 into the upper threaded end of a terminal housing collar I4 which surrounds a tool terminal assembly hereinafter described. The lower threaded end of the terminal housing collar I4 makes threaded connection at l5 with the shouldered intermediate section of a bypass sub I6 which in turn makes threaded connection at Il with the upper end of a length of perforated strainer tubing i8. The strainer tubing |23 is provided with a plurality of radial perforations through its walls as shown at i9 to permit entrance of well fluid into the strainer tubing from which it may now upward through the bypass sub as hereinafter more fully described.

'Ihe lower, threaded end of `the perforated strainer tubing I8 makes threaded connection at with the upper threaded end of a gun head sub 2l. The gun head sub 2| makes threaded connection at threads 22 with the upper end of a cylindrical gun terminal connector housing which in turn makes threaded connection at 24 with the upper threadedend of'a gun perforator body 25.

Referring again, in more detail, to the upper portion of the apparatus assembly, the beforementioned bumper guide housing i2 contains or houses an elongated bumper guide sleeve 25 which has an outer cylindrical surface sheathed in a suitable metal covering 2l of such a diameter as to make a snug sliding fit within the inside diameter of the bumper guide housing. The inner passage through the bumper guide 25 is divergent from either end thereof toward a lower intermediate section of reduced diameter which gives it the appearance of a venturi shaped passage as viewed in cross-section cf Figures l and 2.

An inwardly projecting, annular shoulder formed near the lower end of the bumper guide housing I2, serves as a support for an annular shaped grounding ring 23 which carries a number of inwardly projecting contaetor spring nngers 29.

The lower end of the bumper guide sleeve 2S rests upon theV upper surface of the annular grounding ring 28 and is secured thereon within the bumper guide housing i2 by means of an annular gland 3i), which is adjustably threaded into threads Il in the upper end of the bumper guide housing l2. rPhe bumper guide sleeve E@ may be made of any one of a number of suitable resilient materials such as natural or synthetic rubber and preferably is molded around suitable reinforcing wires or rods as shown at Si.

The inside diameter of the bumper guide sleeve 26 at its throat or section of minimum diameter is preferably of a diameter equal to or very slight* ly less than the maximum outside diameter of the go-devil head member 53 of the go-devil assembly 34, hereinafter more fully described.

The hereinbefore mentioned by-pass sub IE, which is located below and coupled to the lower end of the bumper guide housing l2 .bymeans of the intermediately located terminal housing collar I4, is formed with a lower, central bore or entrance passage 36 which leads, at its upper end, into a plurality of outwardly directed bypass ducts, as shown at 3l. The upper end portion of the by-pass sub, extending above the ducts 3l, is cup-shaped as viewed in cross-section at 58 and serves as a terminal supporting pedestal. The terminal supporting pedestal 38 is enclosed within an intermediate portion of the terminal housing collar lll. Sufficient clearance is provided between the outside diameter of the terminal supporting pedestal 38 and the adjacent inside wall surface of the surrounding contact hous ing collar lei to form an annular passageway as shown at i, through which uid passing through the ley-pass ducts 3l may now.

The terminal supporting pedestal member 33 is provided with internal threads at 4i?, into which is screwed a terminal head member di. The top of the terminal head member l is provided with a cylindrical depression or terminal socket 42. A drilled passage cr bore 43 coaXially interconnects the bottom of the terminal socket i2 with the cavity da formed within the pedestal 3S at the lower end of the terminal head member 5I.

Contained coaxially within the terminal socket d2 are a pair of spaced, concentric terminal members 65 and d. The inner terminal member 45 is substantially cylindrical in shape having an outwardly hanged lower end as shown at i? and internally threaded as shown at d8. The upper end portion of the central terminal member is tipped with a layer of lead or the like soft metalas shown at 45.

The outer concentric terminal member 46 is of a substantially annular or cup-shaped form having an internally threaded portion 50 at its lower end and an upper end surface also carrying an annular covering of soft metal as shown at 5i The terminals 45 and de are held in concentrically and vertically spaced positions with respect to one another by means of a number of insulating bodies comprising a pair of insulating discs 52 and 53, and insulating annular spacer members 55 and 55. The inner terminal 45 is clamped downward in position against the insulating discs 52 by means of a central conductor rod 51 threaded at 48 into the lower end of terminal t5. These insulating bodies may be composed of Bakelite, Formica, Micarta or the like material.

The outer, annular terminal member 46 is clamped down against the insulating disc 53 by means of a conductor tube 59 threaded at 5l) into the lower end of the said cuter terminal me1nber. The conductor rod 5l and surrounding conductor tube 53 are spaced apart within the bore 53 in concentric relation to one another by means of a pair of insulating tubular spacers 6G. The downward clamping force is applied through the conductor rod 5l and the conductor tubing 59 by means of suitable clamping nuts as shown at (il and t2, respectively, which bear upward against suitable insulating washers 63, which insulate them from the lower end of the terminal head member fil.

The upper end portion of the concentric terminal members i5 and i5 are filled in between and covered over by means of a body of soft insulating material as shown at 54 which is clamped downward in close fitting iiuid tight engagement over the ends of the terminals 45 and 46 and against `the upper end surfaces of the insulating annuli 54 and 55 by means of a threaded retainer cap 66. The retainer cap E5 makes screwed connection with the upper end of the contact head member at threads 61.

A pair of insulated conductors 69 and 10 make bolted connection with the lower end of the inner rod conductor 51 and the outer tubular conductor 58, respectively, in the cavity 44 formed below the lower end of the terminal head member 4|. Conductors 69 and 10 lead down through a tubular conduit 1| which passes through the gun head sub 2| and into the interior of the gun terminal connector housing 23 and there makes bolted connection respectively with terminal posts 12 and 13, respectively, of a pair of igniter plugs 14 and 15, screwed` at 16 and 11 into the upper end of the gun body 25. Insulated conductor rods 18 and 19 extend down through the igniter plugs 14 and 15 into igniter cartridge chambers 80 and 8|, where they are grounded to the gun body 25 through fusible ignition filaments 82 and 83.

Suitable lire train or ignition ducts, as shown at 84 and 85, lead from the ignition cartridge chambers 80 and 8| down through the gun body 25, each making connection with a separate group of a plurality of lateral branch ignition passages 80 and 86 leading into the powder or cartridge chambers of a plurality of laterally directed perforating gun units.

The beforementioned tubular conduit 1|, through which the conductors 59 and 10 pass from the lower end of the terminal head member 4| to the terminals 12 and 13 at the upper end of the gun body 25 makes fluid tight screwed connection at 01into a central passage extending down through the lower end of the terminal supporting pedestal 38 from the cavity 44, and this conduit extends downward coaxially through the perforated strainer tubing i8 and centrally through a packing gland B8 into the4 space within the connector housing 23.

The go-devil assembly 34 which is adapted to be lowered down through the drill pipe or tubing I by means of a suitable line or cable 89 and retrieved therefrom by the same means comprises a bail 90, attached to the upper end of a cylindrical sinker and battery containing case 0| l which, in turn carries attached to its lower end the beiorementioned go-devil head assembly 33. The go-devil head assembly 33 comprises a head connector sub 92 which makes threaded connection at 93 into the upper end of a head collar 94. The head collar 94 is formed with a downwardly directed cylindrical recess or opening 95 containing an inner cylindrical shaped contact block 95. The cylindrical contactor block 90 is retained and coaxially spacially positioned within the recess 95 by means of a bolt 91 which passes through a central opening 98 in the bottom of the recess 95 and is insulated therefrom by means of insulation washers 09, |00 and a short length of insulation tubing |0| surrounding the shank of the bolt 91. The upper headed end |02 of the bolt 91 serves as a battery contactor point as hereinafter described.

A pointed contactor member |03 extends downward from a threaded opening |04 formed at one edge portion of the contactor block 95 as shown in Figure 3.

The lower end of the head collar 04 and the contactor block 95 are covered over with a resilient insulating body which may be .com-

The lower pointed end of the contactor member |03 which protrudes beyond the outer surface of the insulating body |05 is normally covered over prior to being lowered against the terminal head assembly as illustrated in Figure 2, with a conical insulating sheath as shown at |01. This insulating sheath |01 is preferably composed of rubber, neoprene or the like insulating material and cemented or otherwise bonded to the adjacent covering material |05 surrounding the contactor |03 to prevent the entrance of any fluid at that point.

In Figure 4 a lower end portion of another form of go-devil head assembly is shown which is similar to and interchangeable with that illustrated in Figures 2 and 3, except that the pointed contactor member |03 is centrally located and extends downward coaxially4 from a threaded opening |06 in the contactor block 95. The lower ends of the head collar 94 and the contactor block are covered over with a resilient insulating body |08 which is similar to that shown at |05 in Figure 3, except fora suitable modification in form to accommodate the centrally located contactor point |03. v

The upper end portion of the sinker and battery container case 90, of the go-devil 34, may be lled with a body of weighting material such as, for example, lead, as illustrated at ||0 in Figure 2. The lower portion of the go-devil case 9| normally contains a plurality of dry cell batteries stacked end to end in series electrical connection as shown at Y The bottom of the case of the lowermost dry cell is supported by, and makes electrical contact with, the beforementioned battery contactor |02 formed by the head of bolt 91. The central top terminal ||2 of the uppermost battery of the series makes electrical contact with a contact button I3 acting under downward compression through a helical spring |14. The batteries are thus connected in series in conventional manner and form a series circuit one pole thereof terminating at the bottom of the go-devil assembly 34 in the pointed contactor point |03 and thel other pole terminating at an intermediate portion of the go-devil in a ground connection comprising the button H3, helical spring H4 and the case 90. As illustrated in Figure 2, the positive pole of the series of batteries is connected to the grounded button H3 Vand the negative pole thereof connected to contactor point |03. The polarity may obviously be reversed by inverting the stack of batteries within the case 90, and in some cases this reversal of polarity may be desirable.

When the go-devil 34 is lowered into the position illustrated in Figure 2, contactor iingers 29 make mechanical and electrical contact with the outside surface ofthe go-devil head collar 94 and thus serve to ground the go-devil case 00 to the bumper guide housing |22 and to the parts of the apparatus associated therewith, including the fluid, if any, within the well borehole. l

The operation of the apparatus is as follows:

The apparatus assembled and having the appearance shown in Figure l, except the go-devil assembly 34 is omitted, is first lowered into the well borehole to a position where perforation operations are to be conducted. The go-devil assembly 34 is next lowered down through the tubing or casing I8 upon the line 89 to a position within the bumper guide 26 approximating that illustrated in Figure 2. The go-devil 34 is then dropped or lowered with sufficient velocity, from the position illustrated in Figure 2, into supporting contact with the terminall head assembly 4| within the contact housing collar I4 where it assumes the position and appearance illustrated in Figure 3. By this downward motion and in this position, the protruding pointed contactor member |83 is thrust through its covering insulating sheath |91 to a position penetrating the insulating body 64 and into Contact with the soft metal 5| on the upper end of the outer annular terminal member 46, as shown in Figure 3. By this operation, an electrical circuit is completed from the batteries I, through bolt 91, contactor block 96, pointed contactor member |03, annular terminal member 46, conductor tubing 59, conductor 13, conductor rod 18 of the igniter plug 14, and thence through the ignition fuse wire 83, in ignition cartridge chamber 8|, to the grounded body 25 of the gun and in return therefrom through the conductive metal portion of the apparatus to the contactor fingers 29, to the metal case of the go-devil 34 and from there through helical spring H4 and contactor button ||3 to the batteries.

The ignition cartridge 8| is thus red, causing in turn, all of the gun units to be red which are connected thereto through the longitudinal ignition duct 84 and lateral branch ignition ducts 86.

Following this, the go-devil 34 may be withdrawn from the well through the tubing or drill pipe I0, by means of the line 89 and the contactor assembly including the head collar 94 of the form shown in Figure 3 removed from the go-devil case and replaced by a head collar having centralized contactor mechanism associated therewith having the form shown in Figure 4, The go-devil 34 may then be again lowered through the tubing or drill pipe l0 to a position within the apparatus as illustrated in Figure 4. In this position the protruding, pointed contactor member |03 penetrates the sheath |01 and the insulating body 64 into contact with the soft metal covering 49 of the central terminal member 45. Electrical contact is thus made from the batteries through the central electrode member 45, conductor rod 51, conductor 69 and through conductor rods 19 in the igniter plug to the ignition filament 82 within the ignition cartridge chamber 83. The ignition cartridge chamber 60 is thus fired causing all of the gun units to be red which are connected thereto through the longitudinal ignition duct 85 and lateral branch ignition ducts 86.

From the foregoing, it is apparent that two or more separate groups of perforating gun units can be separately and selectively fired by employing a suitable arrangement of two or more concentric terminal members of the type illustrated at l5 and 46 in Figures 2, 3 and 4, together with different go-devils or with a go-devil of the type illustrated at 34 having changeable, correspondingly suitable contacter head arrangements of the type illustrated at 94 in Figures 3 and 4.

While, by way of illustration, only two concentric terminal members 43 and 4B have been shown in the construction of the terminal assembly in the terminal head member 4|, any desired number of such concentric terminal members may be employed therein in similar arrangement, within the practical limits set by the space available and size and spacing of terminal members required. The pointed ccntactor members |03 may be suitably positioned in the go-devil head at any desired point on the diameter of the face of the -contactor block 9,6, to accommodate any such modification of the -arrangement and number of terminal members.

The number of gun units or separate groups of gun units which may be separately fired may thus be increased from that shown in the drawings to a greater number, corresponding to the increased number of separate terminal members employed.

The perforator gun illustrated herein may be of any suitable type adapted to be ignited electrically and capable of perforating a casing or the surrounding formations within a Well borehole, such as, for example, the bullet type gun perforator shown in the Zschokke Patent No. 2,326,114. Or, instead of employing a bullet type of gun perforator, a perforator gun may be employed utilizing the so-called shaped charge principal, accomplishing its perforating by the penetrating effect of a high velocity jet of gases projected from the concave or conically formed end of a high explosive body.

After the perforating operations have been completed, as hereinbefore described, any production of well fluid which results therefrom may flow from the well borehole through the perforations I9 into the strainer tubing I8 and thence up through the lateral passages 31 in the -by-pass sub 6 into the annular space 33 between the contact supporting pedestal 38 and the surrounding contact housing collar I4, and thence upward through the bumper guide or pad member 26 into the tubing or drill pipe l0 (the go-devil 34' having been previously retrieved by means of the line or cable 89 or forced upward out of the bumper guide pad 26 by the pressure of the produced uid) and from there upward through the tubing or drill pipe Il) to the usual casing head and production connections at the surface of the well. The apparatus of this invention may thus be employed to perforate the well or casing at the point from which it is desired to obtain production and then the well may immediately thereafter be put on production and permitted to produce through the tubing or drill pipe IU Without the necessity of removing the perforating apparatus from the well. Any detrimental effects of killing the well during the time interval while the gun is removed and suitable production tubing is installed, is thus obviated.

The apparatus of this invention, in addition to the operation hereinbefore described, is also well suited to use in combination with a formation tester or production packer for the purpose of testing a formation or producing a well.

It is to be understood that the foregoing is illustrative only, and that the invention is not limited thereby but includes all modications thereof within the scope of denition of the appended claims.

What is claimed is:

l. Electrical Connector apparatus adapted to be operated while immersed in electrically conductive fluid comprising: a terminal assembly including a plurality of separate concentric terminal members insulated from one another and surrounded by sufficient protective insulation initially to exclude said terminal'members from contact with surrounding iluids, said insulation including a soft insulating layer initially forming a fluid tight covering over one end of said terminal assembly; ago-devil body; an outwardly pointed, axially directed contactor member fixed to and extending from the end Vof said go-devil body, the axis of said contactor member being parallel but positioned laterally with respect to the axis of said go-devil body to penetrate said insulating layer and selectively contact one only of said concentric'terminals when said go-devil body is moved coaxially into forceful end-to-end abutment with the end of said terminal assembly; and guide means associated with said `electrode assembly to guide said go-devil body into such end-to-end abutment with said terminal assembly.`

2. Electrical connector vapparatus adapted to be operated while immersed in electrically conductive fluid comprising: `a terminal assembly including a plurality of separate, concentric terminal members insulated from one another and surrounded by sufcient protective insulation initially to exclude said terminal members from contact with surrounding iluids, said insulation including a resilient convex-shaped bumper body initially forming a iiuid tight covering over at least a portion of one end ofsaid terminal assembly; a go-devil body; an outwardly pointed axially directed'contactor member fixed to and extending from the end of said go-devil body, the 4axisof sai-d contactor member being parallel but positioned laterally with respect to the axis of said go-devil body to penetrate said convexshaped bumper body and selectively contact one of said concentric terminal `members when the said end of said go-devil4 body is moved coaxially to forceful end-to-end abutment with the said convex-shaped bumper body on the end of said terminal assembly; and guide means associated with said electrode assembly vto guide said go-devil body into such end-to-end abutment with said terminal assembly.

3. Electrical connector apparatus adapted to be operated while immersed inelectrically conductive fluid comprising: a terminal assembly includingv a plurality of separata'concentric terminal' members insulated from one another and surrounded by sufficient protective insulation initially to exclude said terminal members from contact with surrounding fluids, said insulation including a resilient convex-shaped bumper body initially forminga fluid tight covering over at least a portion of one end of said terminal assembly; a go-devil body; an outwardly pointed axially directed contactor member attached to and extending from the end of said go-devil body, the axis of said contactor member being parallel but positioned laterally with respect to the axis of said go-devil body; a layer of insulation in the form of a resilient convex-shaped 'bumper body positioned on the end of said go-devil body and of suillcient extent initially to cover and to exclude said contactor member from contact with surrounding fluids, said contactor member being adapted to penetrate said first mentioned convexshaped bumper body and said convex-shaped bumper body on the end of said go-devil body and selectively contact one of said concentric terminal members when said bumper bodies are moved coaxially into forceful and compressive end-to-end abutment with one another; and guide means associated With said terminal asto-end abutment of said bumper bodies with one another.

4. Electrical connector apparatus adapted to be operated `while immersed in electrically conductive fluid comprising: a terminal a-ssembly including a plurality of separate, concentric terminal members insulated from one another and surrounded by suflicient protective insulation initially to exclude said terminal members from contact with surrounding iluid, said insulation including a soft insulating layer initially forming a fluid tight covering over one end `of said terminal assembly; a go-devil body; a source of electrical current in said vgo-devil body; an outwardly pointed axially directed contactor member xed to and extending from the endof said go-devil, the axis of said contactor member being parallel but positioned laterally with respect to the axis lof said go-devilbody to penetrate lsaid insulating layer and selectively contact one only of said concentric terminal members when said endof said go-devil 'body and said end of said .terminal assembly are moved coaxially into end-to-end abutment with one another; means electrically insulating said contactor member from said go-devil body; conductors connecting one terminal of said source with said contactor member and another terminal thereof to said'go-devil body;and guide means associated with said terminalassembly to guide said go-devil body and said terminal assembly into such end-to-end abutment.` Y

`5. Electrical connector apparatus adapted to be operated while immersed inV electrically conductive fluid comprising: a terminal assemblyincluding a plurality of separate, concentric terminal `members insulated from oneanother Vand surrounded by Ysuiiicient protective insulation initially to exclude said terminal members from contact with surrounding fluid, said insulation including a resilient convex-shaped bumper fbody initially forming a :duidtight covering over one end of said terminal assembly; a go-devil body; a source of electrical current in' said go-devilbody'; an outwardly pointed; axially directed contactor member attached'to and extendingfrom the end of said go-devil body, i the -axis of said contactor member being parallel but positioned laterally with respect to the axis of said go-devil body, to rpenetrate the said convex-shaped`bumpe`r body and selectively contact one of said concentric terminal members when said end of said go-devil body and said bumper body are moved coaxially into forceful and compressive end-to-end abutment with one another; means electrically insulating said contactor member from said go-devil body; conductors connecting one terminal of said source with said contactor member and another terminal thereof to said body; and guide means associated with said terminal assembly to guide said go-devil body and said terminal assembly into such end-to-end abutment.

6. Electrical connector apparatus adapted to be operated while immersed in electrically conductive fluid comprising: a terminal assembly including a plurality of separate concentric terminal members insulated from one another; a resilient, convex-shaped bumper body covering at least a portion of the end of said terminal assembly; a go-devil body; an outwardly pointed axially directed contactor member extending from the end of said go-devil body; a resilient, convexshaped bumper body on said end of said go-devil body and having a portion thereof initially covering said contactor member, said contactor member being adapted to penetrate said convexshaped bumper bodies and selectively contact one of said concentric terminal members when said bumper body on said end of said go-devil body and the bumper body on said end of said terminal assembly are moved coaxially into forceful and compressive end-to-end abutment with one another; and guide means associated with said terminal assembly to guide said go-devil body and said terminal assembly into such end-to-end abutment.

7. In well production apparatus having an electrically actuated perforating gun employing an explosive charge and lowered into a well borehole on a tubular suspension member through which fluid produced from the well may flow, the combination comprising: a tubular coupling between said gun and said tubular suspension member; a fluid inlet to said coupling located above said gun, said inlet and said coupling thereby forming a iiuid ow passage from the exterior to the interior of said tubular suspension member; a terminal assembly xed within said coupling above said inlet and dening in part the uid flow passage therethrough from said inlet; an electric terminal member in said assembly and having a surface adjacent the upper end thereof; a fluid tight covering of insulationon said terminal assembly initially excluding said terminal member therein from contact with any uid within said coupling; a tubular guide member comprised of said coupling located above said terminal assembly and adapted to guide the lower end of a gol-devil body passed down said tubular suspension member into abutment with the upper insulation-covered end of said terminal assembly; and an insulated conductor extending through said coupling from said terminal member to ignition actuating means within said gun.

8. In well production apparatus having an electrically actuated perforating gun employing an explosive charge and lowered into a well borehole on a tubular suspension member through which uid produced from the well may flow, the combination comprising: a. tubular coupling between said gun and said tubular suspension member; a iluid inlet to said coupling located above said gun, said inlet and said coupling ythereby forming a uid ow passage from the exterior to the interior of said tubular suspension member; a, terminal assembly xed within said coupling above said inlet and dening in part the iluid flow passage therethrough from said inlet; an electric terminal member in said assembly and having a surface adjacent the upper end thereof; a fluid-tight covering of insulation on said terminal assembly initially excluding said terminal member therein from contact with any fluid within said coupling; a resilient guide member located within said coupling above said terminal vassembly and adapted to guide the lower end of a go-devil body passed down said tubular suspen-sion member into abutment with the upper insulated covering end of said terminal assembly; a fluid-tight conduit extending through the interior of said coupling from within said terminal assembly to Within said gun; an insulated conductor extending through said conduit from said terminal member to ignition actuating means within said gun; an elongated go-devil body adapted .to be passed down said tubular suspension member; an outwardly pointed, axially directed contactor member extending from the lower end of said go-devil body; a resilient, convex-shaped bumper body of insulating material on said lower end of said go-devil body and having a portion thereof initially covering said contactor member, said contactor member being adapted to penetrate said convex-shaped bumper body and said fluid tight covering of insulation on said terminal assembly into contact with said terminal member when said go-devil body is lowered through said .tubular suspension member and through said guide member into abutment with the upper end of said terminal assembly.

GEORGE F. TURECHEK. ROBERT A. PHILLIPS.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 2,339,274 Kothny Jan. 18, 1944 2,396,768 Ahlgren Mar. 19, 1946 2,427,377 Zschokke Sept. 16, 1947 2,441,894 Mennecier May 18, 1948 

